Two different sets of union workers walked off the job last week, stalling hundreds of construction projects throughout Chicago and Illinois.

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"We were hopeful that we were going to make great strides in negotiations today. Unfortunately that is not what happened," said Mid-America Regional Bargaining Association spokeswoman Lissa Druss Christman.

The engineers and laborers had been working without a contract for a month and want a 15 percent wage increase over three years to offset the cost of health care. The bargaining association, which represents the construction companies, offered only a 3.25 percent hike over three years.

Union representatives said their only option was to hit the picket lines.

"They forced our hand," said Ed Maher, spokesman for International Union of Operating Engineers Local 150 to the Chicago Tribune. "We're simply not going to get jerked around when we're worried about maintaining health care for more than 23,000 members."